Magnet support for radio speakers



Dec.- 12, 1950 D. G. MUNSQN MAGNET SUPPORT FOR RADIO SPEAKERS Filed June l9, 1948 Patented Dec. 12, 1950 UNITED STATES PATENT OFFICE MAGNET SUPPORT FOR. RADIO SPEAKERS Donald G. Munson, St. Paul, Minn. Application June 19, 1948, Serial No. 33,981

3 Claims.

My invention relates to an improvement in radio speakers and deals particularly with the manner in which the magnet thereof is supported.

In the manufacture of radio speakers, it is common practice to form a round or rectangular metallic pot for conducting the magnetic flux from one pole to a point spaced from the other. The pot or holder is usually provided with an aperture into which one end of the magnet or pole piece extends, the walls of the aperture being spaced from the magnet or pole piece a distance sufficient to allow the speaker coil to be interposed therebetween. The magnetic flux is conducted from the opposite end of the magnet so that the coil may extend between metallic walls of opposite polarity.

The object of the present invention is to produce a speaker at an extremely low cost of production and which is efficient and effective in operation.

A feature of the present invention lies in the provision of means for automatically aligning the magnet with the aperture in the pot. Care must be taken to center the magnet within the aperture as the air space or gap therebetween is extremely small. With my novel construction the magnet and aperture are automatically aligned.

A feature of the present invention lies in the provision of a speaker pot formed of two parts arranged in abutting or telescoping relation. One of the parts is provided with an aperture for accommodating the magnet. The other part is provided with an aperture into which the magnet extends. When the two parts are assembled the magnet is automatically centered with respect to the aperture.

A feature of the present invention lies in the provision of a speaker pot which may be easily formed in a punch press or the like. The parts of my speaker pot are cup shaped in form and may be drawn into finished position by means of a punch press. Thus the cost of producing the speaker pot is maintained at a minimum.

A feature of the preferred form of my construction lies in the provision of a cup shaped element having a central aperture formed therein which may if desired be drawn into a central boss orsleeve. This aperture supports the magnet and holds the same centered with respect to the remainder of the part.

A further feature of the present invention lies in the provision of a two part pot for a loud speaker in which the parts are interfitting so that the magnet supported by one part will be in proper relation to the aperture formed in the other part,

These and other objects and novel features of my invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of my speci fication:

Figure 1 is a rear elevational view of a loud speaker showing the general construction thereof.

Figure 2 is a plan view of the speaker illustrated in Figure 1.

Figure 3 is a sectional view through the speaker showing the pot construction.

Figure 4 is an elevation view of the magnet removed from the speaker.

Figure 5 is a sectional view through a modified form of pot construction.

The loud speaker A illustrated in the drawings may be of any suitable type or design, one such construction being illustrated. The speaker A includes a metallic frame or spider 19 which acts as a support for the cone shaped diaphragm l I. The frame I 0 is provided with a ring shaped periphery l2 to which the periphery I3 of the diaphragm H is secured. The speaker pot is illustrated in general by the numeral I4 and is secured to the spider or frame near the center thereof. The center portion of the spider I0 is provided with an aperture l5 and the portion of the spider adjacent this aperture is off-set as indicated at E6 for attachment to the pot M. The pot may be welded or otherwise aflixed to the spider and is concentric with relation there to.

A sleeve 11 of paper or other suitable material projects rearwardly from the center of the cone and acts to support the speaker coil i9. The coil I 9 is supported near the extremity of the sleeve IT and is arranged in the gap between the portions of the pot which are of opposite polarity.

As indicated in Figure 3 of the drawings the speaker pot l4 includes a pair of opposed cup shaped elements 20 and 2|. The member 20 includes a generally cylindrical peripheral flange 22 and a disc like wall 24 at the forward end thereof. The wall 24 is provided with an aperpot and ture 25 therethrough which is coaxial with the cylindrical sleeve or wall 22.

The member 2! also includes a cylindrical wall 26 and a'disc like wall 2! secured integrally toone end thereof. The members 20 and 2| are identical except for the aperture 25 in the mem ber 20. The pot members 20 and 21 are designed to lie in edge abutting relation as illustrated.

A magnet supporting member 29 is arranged within the cup shaped elements 20 and 2|. The

} member 29 includes a cylindrical sleeve 3Bhaving a ring like inwardly extending flange 13! issuing from one end thereof. A concentric sleeve 32 is provided on the flange 3! extending in spaced relation to the cylindrical wall 30 and" concentric therewith. A cylindrical magnet 33 is supported by the sleeve 32 and is of sufficient length to extend into or through the aperture 25. If it is preferred the magnet 33 can include a shorter length of magnetic material With a pole piece secured coaxially therewith'and extendin from one end thereof.

In the construction of my speaker pot the pot membersflfl and 321 .are preferably drawn from a sheet of 'iiat metal into the cup shape form. The aperture 25 is punched in the pot wall 24 preferably simultaneously with the formation of the member 26. As both of the members 20 and 2| may be mainly formed on the same die the cost of manufacture is low.

The inner magnet support 29 may hegpressed' of somewhat thinner material and maybe'formed or drawn on a punch press or the like. Asa'result the inner member 29 may be economically con- 'structedin-volume.

.In-assembling the speaker -potthe magnet 33 is pressed into the sleeve 32 so as to extend coaxial therewith. As the sleeve 321's coaxial with the outer shell or sleeve 31! the magnet-is centered within its support.

The supporting member .29 is preferably next pressed into the pot member .20 .so that the free edge of the wall 30 .is in overlapping or telescoping irelation with the wall 12 :of thesmembersfll. the wall Si is concentric or coaxial with ,the magnet and .as :the aperture 25 is coaxial with the waII Z-Lthelmagnet will extend in coaxial. relation to the .aperture. The magnet is of sufficient length in preferred .form to extend through the aperture 25 land is spaced :fro nthe walls-of the aperture .a distance-sufiicient to accommodate .the paper sleeve lfiiand-ithe coil Lil wound there- .about. Breferably the .coil is located directly between the endportion of the magnet and-the walls of theapertureso as to be influenced by the force of the magnet.

The pot member 21 may next be telescoped over themember 29 until the free edges of the walls 22 and 26 abut. "Theend of the magnet is preferably-in contact '-with the inner surface of the wall :21. The three parts of thepot may benierely held together by friction or if preferred may he welded or otherwise connected. Furthermore, the potmay be assembled as described-either before the pot member .2 is attached to the spider Ill-or after this .attachmenthas been made.

In Figure lofthe drawings I-disc-lose a modifled form of speaker pot illustrated in generalby the numeral 34. This pot 34 is formed of two parts .rather than the three parts previously described. However, the structure of :Fig-ureS has the disadvantage that the abutting edges of the two sections must be machined .or otherwise shaped to interfit.

The speaker pot -34 includes two cup shaped sections 35 and 36. The sect-ionz35 includes :a generally cylindrical outer wall 3:1"a-ndan end closure wall 39 having a central aperture '40 therein. The pot section 36 includes a generally cylindrical outer wall 44 and an end closure wall 42 having a central aperture 43 therein. The aperture 43 is somewhat smaller in diameter than the aperture-en and'the cylindrical magnet is pressed into the aperture 43 to extend coaxial with the outer sleeve '36. The magnet 44 is also of .sufiicient .length to extend'throug'h 0r SHb'. stanti-allythroughthe aperture in in the :closure wallafland iscoaxial therewith.

A peripheral groove 55 in 'thefree edge of the cylindrical wall :31 is designed to accommodate the projecting tongueor flange 46 on theiree edge ofethe wall fil The interfittingof the tongue. 46 into the groove 45 holds the two parts of the speaker pot properly aligned. Obviously both sections of the potare of equal outer diameter andinterfit in the manner .described.

been described an important feature of my structure flies in "the fact that when 'ithe speaker is assembled all of the parts au'tomatically align. Secondly the pot construction is inexpensive as the parts thereof may be formed on a punch press orsimilardevice. Furthermore, it should be noted that the pot forms an enclosure for the magnet JandeIiminateS the necessity of providing gaskets or other seals for closing the gap'between the magnetand'the pot. With the conventional constructiona gasket is provided between the magnet and the pot so as to prevent dust and dirt from entering thegap.

.Inac'cordance with the patent staltu'tes,lIhave described .theiprinciplesof construction and ,operation of my radio speakers, and while Tihave endeavored to set .forth .the best embodiment thereof, .I desire .to have .it understood .that. obvious changes may bemade within the scope ofthe followingclaims without departing from thespir'it of my invention.

.Iclaim:

.1. .A speaker pot including a cupshaped ele ment having acylindrical outer wall and an iinte-' gral endclosure, said. end closure .having anaxial aperture therein, a magnet supporting element including a cylindrical wall in telescopingrelation andfrictional .contactwith the wall of said cup shaped element, a ring like 'flange on said cylindrical wall, and. a sleeve integral with said ring like flange .and concentric with said cylindrical wall of said magnet support, anda magnet supported in frictional contact with said sleeve and extending into said aperture.

2. The structure described in ..c1a'im -l .an'dl ineluding a second cup shaped. element arranged in edge. abutting relation with .the first namedcup shaped element and contacting the cylindrical Walland the flange ofsaid magnet supporting element.

3. A speaker pot including a pair of generally cup-shaped elements arranged in edge abutting relation, a -magnet support including .a .cup shaped body having an outer wall in frictional contact with the outer wall of one ofsaid cupshaped elements and having .a disc-like flange connected to the outer wall and in contact with the 'base of saidone cup-shaped element, the peripheral wall of the magnet support extending beyond the end of said one cup-shaped element, an integral coaxial sleeve on said disc-likefiange coaxial with the peripheral wall of the magnet support, -.a magnet frictionally engaged within said sleeve and having one end in contact-with.

said one cup-shaped element, the other cupshaped element having an aperture thereth-rough.

coaxial with the peripheral wall: thereof, the other end of. said magnet extendin into said aperture, said other cup shaped element beingin frictional contact with the projecting portion of said magnet support.

DONALD G. MUNSON.

REFERENCES 0mm The following references are of record in the file of this patent:

UNITED STATES PATENTS 

